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Canaloplasty Glaucoma Surgery

Using Mastel Instruments: Part 4 – Suture

And I’m just going to trim the end. I don’t want to trim it too short. Again, I don’t want something sticking out that’s going to lacerate the canal. OK. And what I’m doing right here is I’m actually having my technician click the injector so I can see that I am, in fact, getting some viscoelastic moving through the catheter and coming out the tip. And now, very carefully… Also important there, is I’ve taken care that there’s absolutely nothing that could hang the Prolene suture. So I’ve confirmed that the entire length of that Prolene suture is, in fact, free of anything that could hang it up.

So now I’m going to slowly and smoothly pull the catheter back out through, using the combination of Fechtner’s and the Mastel modification of the Fechtner’s. And I’ll be calling out “click, click, click,” every three to four clock hours, so that I get a fair amount of viscodilation. Now it’s all the way through. And what you can’t see here is that I’m holding onto that catheter there. Cut the suture, very carefully passing it off. Then before I actually let my staff pull the catheter away, I grab onto that Prolene suture. I have had an unfortunate experience with the catheter being pulled away and the Steri Strip that was holding the catheter then grabbing hold of the Prolene and pulling the Prolene out, which requires, then, recanalization. So you want to be very, very, very aware of just where everything is. Slow, deliberate movements with this surgery.

Now what I’m doing is what’s called flossing the canal, which looks just as it sounds. And now I’m going to go ahead and tie the suture using an adjustable knot. And placing an instrument over the long end of the suture, looping the suture, the long end, around the instrument, grabbing the short end and crossing the instruments over. And that’s standard.

The second tie is what’s absolutely critical for this particular knot. So, again, I’m going to place the instrument over. So, over the long arm here. And when I say over, I mean between the long and the short arms. So if you lie them down… There we go. Let’s go over the suture. So I’ll start here. Over the suture, wrap the suture around. And now, instead of pulling the short end across, to the opposite side, I keep the short end on the same side as it was previously positioned, and that’s what allows me to tension this and adjust it.

I’m now going to use what’s called the “slack pull” method. So, I’ve got the short end on the same side as it was previously located, and as long as it’s there, I can adjust it. I’m going to take both ends and, right here, I’m just going to pull on them, and I should be able to pull out to about the area of Schlemm’s canal, with a fair amount of tension. And now I’m happy with that, so I go ahead and I lock it. And I lock it by just bringing the short end and the long end opposite of where they were. Now I’ll throw a couple of extra passes. So I’ve locked it, and now this is just going to give me the security of locking down the lock.

Good. OK. That’s it. It’s locked down. We’ve got a good trabeculo descemetic window there. Now what I’m going to do is I’m just going to cut the ends of the suture. And cut it pretty close, but you want to make sure that you don’t get the tips of those Vannas scissors anywhere near that trabeculo descemetic window.

So now traditionally, this part here, removing or cutting the deep flap, has been challenging. One, because if you don’t get a good window then every little bit of that deep flap that you leave is going to cover up your window. But when you have a nice thousand micrometer plus window, it gives you a fair amount of leeway here.

Also if you’ve done a good blunt dissection with the CP manipulator, you’ve got a potential space between the deep flap and the Descemet’s, which again gives you a little bit of a comfort zone there. So I’m just exposing this deep flap, and I’m going to take the angled Vannas and just cut off the deep flap here, taking care that the blades are not anywhere near the trabeculo descemetic window, TDW.

That’s one thing about using the scissors is, as you can see, that portion of the flap close to where you start the cut, there’s always a bit more of a lip there. But even so you can see that I have well over 500 micrometers in the least exposed area of the window. And close to 1,000 micrometers in the most exposed. And that’s just showing you using the CP manipulator.

So now I have an exposed window, got a good bed there, I’m going to fill the bed with viscoelastic, and bring down the superficial flap. And now we’re ready to close.

David Richardson, MD

Medical Director, San Marino Eye

David Richardson, MD is widely recognized as one of the top cataract and glaucoma surgeons in the US and is among an elite group of glaucoma surgeons in the country performing the highly specialized canaloplasty procedure. Morever, Dr. Richardson is one of only a few surgeons in the greater Los Angeles area that performs Micropulse® "Cyclophotocoagulation" (MP3) glaucoma laser surgery. Dr. Richardson graduated Magna Cum Laude from University of Southern California and earned his Medical Degree from Harvard Medical School. He completed his ophthalmology residency at the LAC+USC Medical Center/ Doheny Institute. Dr. David Richardson is also an Adjunct Assistant Professor of Clinical Ophthalmology at Keck School of Medicine of USC. Twice weekly, he treats veterans at the VA Greater Los Angeles Veterans Healthcare System. → Learn more about Dr. David Richardson